Why wont our government close our borders?

this is a ongoing problem for america this has benn going on for years our government has refuse to close our borders and now you have a drug war in Mexico this is a very violence and deadly war and it is getting worse every day many people who live near the american/mexico border are scare for there lives many are choosing to move away and still our government refuses to close our borders why . we are the only country on the planet that will not protect our borders this is insane . what will it take to get our government to close our borders is anyone else as upset as i am about this